For safety reasons, tractors, lawn and garden vehicles, and riding mowers may be provided with some form of rollover protection system, or ROPS, to prevent the vehicle from crushing the operator if it accidentally rolls over. The ROPS should be capable of supporting the forces generated by the weight of the vehicle in the event of a rollover, maintaining free space for the operator to reduce the danger of injury.
If a cab is provided, the ROPS may be built into the cab. If a cab is not provided, the ROPS may consist of a generally U-shaped crossbar located above the head of the operator, and legs connected to the vehicle frame.
The ROPS may be straight tubing, and brackets may be welded to the legs or lower section to connect the ROPS to the vehicle frame. The legs or lower section of the ROPS may be welded in a position perpendicular to the vehicle frame. A ROPS is designed to absorb energy from the weight of the vehicle, and the brackets transfer energy from the ROPS to the vehicle frame. As a result, the welded brackets may need to be reinforced to withstand the transfer of energy, adding to the cost of the vehicle. A ROPS is needed that can provide greater energy absorption and have less welded bracketry.
Some ROPS may be adjustable to decrease the height of the ROPS in certain situations. For example, U.S. Pat. No. 4,877,265 relates to a ROPS that is easily adjustable between different heights, and U.S. Pat. No. 4,949,991 relates to a ROPS that can be folded from a raised position to a lowered position.
Some riding mowers, such as zero turn radius mowers, have a folding ROPS connected to the vehicle frame on each side of an operator station. However, the vehicle may have a rear mounted engine that can block the ROPS from folding down completely. The folded upper section of the ROPS may extend beyond the rear dimensions of the vehicle frame and/or body. As a result, the folded ROPS increases the length and/or height of the vehicle. The increased dimensions add to the square footage needed for vehicle storage and vehicle transportation on a truck or trailer, and also may hinder mowing in and around tight spaces such as around trees with overhanging limbs. A ROPS is needed for an off road vehicle such as a riding mower with a rear-mounted engine that can be folded down to a lowered position to minimize vehicle length and/or height.